1. Field of the Invention
This invention relates to methods and kit for aid in diagnosing tick borne illnesses, including lyme. disease.
2. Description of the Related Art
Lyme disease is the most prevalent vector-borne disease of humans in the United States and is transmitted by the bite of Ixodes ticks. Infection is caused by the bacterium Borrelia burgdorferi resulting in an illness affecting various organ systems of the body. The clinical implications of Lyme disease can be seen in dermatologic, neurologic and rheumatologic manifestations. (1-5)
In Lyme disease two stages of the disease, acute and chronic, are considered. These stages may occur separately or may overlap. Neurological disorders (such as Bell's palsy, meningitis, encephalitis), cardiovascular cardiac arrhythmia, and disorders of the musculoskeletal system (migrating pain in muscles, tendons or joints) are possible in Lyme disease. If left untreated, the patient may acquire chronic lyme borreliosis. (6-8)
No matter what causes the manifestation of Lyme disease, the key to avoiding serious effects is prompt diagnosis and treatment of the underlying disorder. Early detection of Lyme disease is difficult because the characteristic rash is not evident. The flu-like symptoms which can be caused by many other factors are added to the severity of the problem. Many assays used in laboratories are unreliable. Therefore, it is advantageous to combine clinical symptomatology with a sensitive technique available to diagnose lyme disease. (9-15)
Lyme ELISA
The Lyme ELISA test is intended for the qualitative detection of IgG and IgM antibodies to Borrelia burgdorferi in human serum. Titers of IgG are generally low during the first weeks of illness. They peak three months to a year after infection and may remain elevated for years. Titers of IgM peak within three to six weeks after onset but are often not detectable in asymptomatic patients. (9,13,16)
Lyme Western Blot Assay.
The Western Blot Assay has been widely used to detect the presence of antibodies in human serum and plasma to various infectious disease agents. In this procedure, component proteins of purified, inactivated virus are electrophoretically separated by SDS-polyacrylamide electrophoresis followed by electrotransfer to nitrocellulose sheets. Each strip serves as the solid-phase antigen for an ELISA test.
Other Methods.
Culturing Borrelia burgdorferi from clinical samples other than erythema migrans lesions is difficult. PCR-based methods seem to be insensitive for routine lab testing due to absence or low number of bacteria in clinical samples.
The mainstay of laboratory diagnosis for Lyme disease has been Serological Assays. However due to antigenic diversity used in the assays their performance in different laboratories is highly variable (16-22).
The Western Blot Assay is more reliable since the cross-reactive antibodies are relatively excluded and peptide specific antibodies in the form of bands are observed. However, due to antigenic variations, if antibodies are not present in the blood, false negative results will be obtained (23-25).